This invention relates to a telephone system having a telephone transfer function. The invention also relates to a telephone having a temporary holding function in which, when a party to a conversation is put on hold, the party is capable of sending a message to the party which initiated the hold or of cancelling the holding state.
In a telephone transfer function of a conventional telephone system, a channel is formed between a first telephone and a second telephone and, during; a conversation between the two telephones, one of the telephones, say the first telephone, issues an instruction to put the call on hold, places a call to a third telephone, waits for a response from the third telephone and, when a response is received, connects the second telephone, which has not input a transfer instruction, to the responding third telephone, thereby transferring the held call to the third telephone. Since the second telephone is in the holding state once processing for the transfer starts, it is incapable of taking any action whatsoever until transfer processing ends.
Specifically, in a telephone exchange system shown in FIG. 13, when a conversing party using a telephone A 1 requests of a conversing party using a telephone B 2 that the connected call be transferred to a telephone C 3 during a conversation between the telephones A 1 and B 2, an exchange unit 30 places the call between the telephones A 1 and B 2 on hold, subsequently executes call processing for placing a call from telephone B 2 to telephone C 3 and, when telephone C 3 responds, connects telephone A 1 and telephone C 3 to transfer the held call.
In the above arrangement, no means are provided for allowing the party of telephone A 1 that requested the transfer to contact telephone B 2 during the transfer operation between telephone B 2 and telephone C 3. This is disadvantageous for the following reason: If party A requesting the call should urgently need to get in touch with party B, as in a case where party C which is the destination of the transfer suddenly shows up in person at the location of party A, it is necessary for party A to wait until the transfer to party C is completed or until party B is reconnected with party A.
A long period of time is often required for the transfer and call between parties B and C. In such case, all three parties, namely party A requesting the transfer, party B and party C waste time. This is also a cause of line crowding. Thus, once a call has been put on hold in a conventional telephone, the holding state cannot be cancelled unless this is instructed on the side that initiated the hold, and the side that has been put on hold is entirely incapable of sending and receiving messages. In the prior-art arrangement, therefore, the party put on hold is constrained to wait one-sidedly without knowing for how long.
In other words, when a party is put on hold by a telephone having a holding function, the cancellation of the holding state depends entirely on the side that initiated the hold, so that the holding side does not know how long the holding state will last and must wait until this state is cancelled, during which time the holding side can take no action. This is extremely inconvenient. Even if the holding side wishes to have the other party cancel the holding state, there is absolutely no way in which the other party can be so informed. The only recourse to escape from the holding state is for the holding side to hang up, thereby cutting off the line being held and, in effect, terminating the call.